Advances of Researchs on Molecular Mechanisms of Mesenchymal Stem Cells and Their Exosomes in Angiogenesis--Review / 中国实验血液学杂志

Mesenchymal stem cells (MSC) have the potential of multi-directional differentiation, and can recruit endothelial cells, promote their proliferation, migration and angiogenesis, improve blood perfusion and oxygen suppliment, and repair damaged tissue. Exosome secreted by MSC contain mother cell-specific proteins, lipids and nucleic acids, and acts as signaling molecule, playing an important role in cell communication, thereby altering target cell function. In this review, the biological characteristics of MSC and its exosome, the mechanism of promoting vascular regeneration in patients with ischemic diseases, and the mechanism of hypoxia-inducible factor-1α（HIF-1α） in the vascular ischemia of ischemic diseases are all summarized briefly.

Palmitate induces apoptosis and endoplasmic reticulum stress in human umbilical cord-derived mesenchymal stem cells / 生理学报

The saturated free fatty acid (FFA), palmitate, could induce apoptosis in various cell types, but little is known about its effects on human umbilical cord-derived mesenchymal stem cells (hUC-MSCs). Here, we investigated whether palmitate induced apoptosis and endoplasmic reticulum (ER) stress in hUC-MSCs. hUC-MSCs were stained by labeled antibodies and identified by flow cytometry. After administration with palmitate, apoptotic cell was assessed by flow cytometry using the Annexin V-FITC/7-AAD apoptosis detection kit. Relative spliced XBP1 levels were analyzed using semi-quantitative RT-PCR. The mRNA of BiP, GRP94, ATF4 and CHOP were analyzed by real-time PCR. Relative BiP and CHOP protein were analyzed using Western blot analysis. The results showed that hUC-MSCs were homogeneously positive for MSC markers; palmitate increased apoptosis of hUC-MSCs and activated XBP1 splicing, BiP, GRP94, ATF4 and CHOP transcription. These findings suggest that palmitate induces apoptosis and ER stress in hUC-MSCs.

A novel missense mutation resulting in X-linked adrenoleukodystrophy in female heterozygotes of a Chinese family / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify ABCD1 gene mutation in a Chinese family with three heterozygous female patients.</p><p><b>METHODS</b>Four fragments covering the entire coding sequence of the ABCD1 gene from one of the female patients were amplified by reverse transcription-PCR. The PCR products were directly sequenced. The result of sequencing was confirmed by restriction enzyme digestion of PCR products from genomic DNA. Human ABCD1 gene and ALD protein were aligned with those of rat, monkey, mouse and cattle by Clustal X 1.83. Softwares of Motif Scan, TMpred and ESYpred3D were used to predict the effect of the mutation on the structure of the ALD protein.</p><p><b>RESULTS</b>A novel missense mutation, CAC to CGC, was found at codon 283 of the ABCD1 gene from the patient, resulting in the replacement of histidine by arginine. This mutation abolished an Msl I site in the gene. Her son was free from this mutation. The mutated amino acid residue (283H) was highly conservative in evolution, and the mutation caused a dramatic change in the structure of the ALD protein.</p><p><b>CONCLUSION</b>Three female patients heterozygous for ABCD1 gene mutation were first reported in China, and a novel mutation, p.H283R, was identified in this X-ALD family.</p>

Prenatal diagnosis of 5 fetuses with high risk of developing spinal muscular atrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To perform prenatal diagnosis for 5 pregnant women who had given birth to children with spinal muscular atrophy (SMA).</p><p><b>METHODS</b>Thirty to forty mililiters of amniotic fluid was obtained by amniocentesis under ultrasonic monitoring. DNA was extracted directly from sediment of amniotic fluid. Short tandem repeat (STR) profiling was carried out to evaluate the contamination of amniotic DNA by maternal genomic DNA. Two methods, PCR-restriction fragment length polymorphism (PCR-RFLP) and allele-specific PCR, were used to analyze exon 7 of SMN gene from amniotic DNA.</p><p><b>RESULTS</b>Comparing the 16 STR sites of each fetus with those of his/her parents, there was no or little contamination of amniotic DNA by maternal genomic DNA. In conventional PCR-RFLP, part of the PCR product (189 bp) from amniotic DNA of fetus A, C, or D remained intact after digestion with Dra I, while the PCR product from amniotic DNA of fetus B or E was completely digested by Dra I. In allele-specific PCR, exon 7 of both SMN1 and SMN2 gene could be seen when amniotic DNA of fetuses A, C, or D was analyzed, while only exon 7 of SMN2 could be seen when amniotic DNA of fetuses B or E was analyzed.</p><p><b>CONCLUSION</b>Homozygous deletion of SMN1 is not detected in fetuses A, C, and D, predicting that the risk of developing SMA after birth would be extremely low. Homozygous deletion of SMN1 was present in fetuses B and E suggesting high risk of developing SMA after birth.</p>

Avoiding the interference of ABCD1 pseudogenes in the molecular diagnosis of X-linked adrenoleukodystrophy by double amplification refractory mutation system / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To avoid the interference of ABCD1 pseudogenes, the amplification refractory mutation system (ARMS) was used to analyze the mutation of ABCD1 gene in the molecular diagnosis of X-linked adrenoleukodystrophy (ALD).</p><p><b>METHODS</b>The upstream primers (wild primer and mutation primer) were designed according to the principle of primer-design in ARMS. In addition, a common downstream primer was designed in the same way to discriminate ABCD1 gene from its prologous pseudogenes. The genomic DNA isolated from the peripheral blood leukocytes of the family members and normal controls was amplified by PCR.</p><p><b>RESULTS</b>In double ARMS, a specific product of 107bp could be amplified from genomic DNA of the patient with R617C mutation in ABCD1 gene and his mother, while the same product was not found when the genomic DNA of the patient's father and normal controls was used. Thus, the interference of ABCD1 pseudogenes in molecular diagnosis of ALD was excluded successfully at genomic DNA level.</p><p><b>CONCLUSION</b>Double ARMS is a quick and effective method to eliminate the interference of the pseudogenes in detecting ABCD1 gene mutations.</p>

Prenatal molecular diagnosis of adrenoleukodystrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To carry out prenatal diagnosis on two fetuses of different pedigrees with X-linked adrenoleukodystrophy (ALD).</p><p><b>METHODS</b>The amniotic fluid was obtained with the help of a clinical doctor and the genomic DNA was isolated from it. Maternal DNA contamination was excluded by fluorescent STR profiling, The R617G mutation found in the first pedigree was searched in genomic DNA of amniotic fluid cells (AFC) from fetus 1 by amplification refractory mutation system (ARMS) and dot DNA hybridization while the P534R mutation found in pedigree 2 was analyzed in the AFC genomic DNA of fetus 2 by restrictive digestion with Hae II and DNA direct sequencing.</p><p><b>RESULTS</b>A specific band (185 bp) was detected from the genomic DNA of the first fetus and his mother by using mutation primer in ARMS but not from that of the first fetus's father and unrelated controls. DNA dots were visualized only in the fetus 1 and carrier when using the mutation probe in DNA hybridization. In the other ALD family, the PCR product (506 bp) of the second fetus which spanned the site of P534R mutation could not be digested with Hae II and no mutation was detected in the ABCD1 gene from the genomic DNA of the fetus 2 by using DNA direct sequencing.</p><p><b>CONCLUSION</b>Fetus 1 had R617G mutation on his ABCD1 gene and he was an adrenoleukodystrophy hemizygote. Fetus 2 had no P534R mutation on his ABCD1 gene and he was a normal hemizygote.</p>

Mutational analysis of three Chinese pedigrees with adrenoleukodystrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify the mutational genotype of three Chinese families with X-linked adrenoleukodystrophy (X-ALD: MIM#300100).</p><p><b>METHODS</b>Total RNA was extracted from the peripheral blood leukocytes of patients 1, 2 and the mother of patient 3, using RNA blood Mini kit (QIAGEN). After reverse transcription, cDNA was amplified in four overlapping segments. The PCR products were purified and directly sequenced. To confirm the mutations, the genomic DNA was isolated from the patients and their family members using DNA blood isolation kit (MO-BIO) and analyzed by PCR-restrictive digestion or amplification refractory mutation system.</p><p><b>RESULTS</b>Three distinct mutations were detected in the ABCD1 gene of the three pedigrees. A mutation of CCC-->CGC was detected at codon 534 of the ABCD1 gene from patient 1, resulting in the arginine for proline substitution. A change of GGG-->AGG was found at codon 266 of the second patient's gene, accompanied with the replacement of glycine by arginine. A mutation of CGC-->GGC was found at codon 617 in one ABCD1 allele of the third patient's mother, leading to the glycine for arginine substitution. The three mutations were confirmed through restriction analysis or amplification refractory mutation system.</p><p><b>CONCLUSION</b>Three ABCD1 gene missense mutations were detected in three unrelated Chinese families with X-linked adrenoleukodystrophy, one of which, the mutation (P534R), is novel in Chinese with ALD, and the other two G266R and R617G mutations, have been reported outside China.</p>